Electronic stove and universal power supply
An electronic stove incorporates a cylindrical outer shell and a concentric copper heater core. A foil heater surrounds the copper heater core and a heater control PCB carried in the outer shell is connected to the foil heater. A battery assembly has a cylindrical second outer shell carrying a battery pack. A power controller carried in the second outer shell is connected to the battery pack. A connector carriage is engaged between the battery assembly and cylindrical outer shell, extending through the shell of the battery assembly and received in the cylindrical outer shell aligned proximate a lower surface of the first outer shell whereby the lower surfaces of the first outer shell and the second outer shell are in planar alignment. A first contact set of a connector is connected to the heater control PCB. A second contact is connected to the power controller.
This application is a divisional application of U.S. Ser. No. 16/576,383 filed on Sep. 19, 2019 entitled ELECTRONIC STOVE AND UNIVERSAL POWER SUPPLY which claims priority of U.S. provisional application Ser. No. 62/734,220 filed on Sep. 20, 2018, the disclosures of which are incorporated herein by reference.
BACKGROUND FieldThis invention relates generally to the portable cooking systems and more particularly to an integrated heating vessel and battery assembly.
Description of the Related ArtCamping or backpacking stoves are highly useful for remote operation when other cooking facilities are not available. Propane or butane heater systems are available which provide adequate heat to boil water or generally heat meals with high liquid content. However, open flame is always potentially hazardous.
It is therefore desirable to provide a device which provides capability for heating liquids and high liquid content meals which is easily portable but does not employ a flame heater.
SUMMARYThe embodiments disclosed herein overcome the shortcomings of the prior art by providing an electronic stove (E-stove) incorporating a liquid container and heater system (LCHS) having a substantially cylindrical outer shell and a copper heater core concentrically received in the outer shell. A foil heater is concentrically received around the copper heater core and a heater control PCB is carried in the outer shell and operationally connected to the foil heater. A battery assembly having a substantially cylindrical second outer shell and a battery pack carried within the second shell. A power controller printed circuit board (PCPCB) is carried in the second outer shell and operationally connected to the battery pack. A connector carriage, extendable from the battery assembly proximate a lower surface second outer shell is adapted to be engaged between the battery assembly and the liquid container and heating system in an operating mode. The connector carriage removably extends through a first aperture in the second cylindrical shell of the battery assembly and is received through a second aperture in the first cylindrical shell of the liquid container and heating system. The second aperture is proximate a lower surface of the first outer shell and aligned with the first aperture whereby the lower surface of the first outer shell and lower surface of the second outer shell are in planar alignment. A first contact set of a connector is carried by and operationally connected to the heater control PCB. A second contact set of the connector is carried by the connector carriage and operationally connected to the power controller printed circuit board.
The disclosed implementations provide a method for heating of a liquid container and heating system (LCHS) having a copper heating core. An input for a desired heating mode and a target temperature is received. If the desired heating mode is a boost mode, full available power is provided to a foil heater concentrically surrounding the copper heating core. Battery pack condition is measured and temperatures of a first thermistor located proximate a top of the copper heating core, a second thermistor located centrally on the copper heating core and a third thermistor located proximate a bottom of the copper heating core are measured. A dwell phase is entered when the third thermistor reaches the target temperature and power is removed from the foil heater. Temperatures of the first, second and third thermistor are measured and, if battery pack condition is within acceptable limits, power is provided to the foil heater upon measured decrease in temperature of all thermistors. The dwell phase is then repeated.
Alternatively, if the desired heating mode is an eco mode, initial temperatures of the first, second and third thermistors is measured and battery pack condition is measured. A target temperature and estimated power are computed to reach the target temperature based on battery pack condition. A heating cycle is started providing the estimated power to the foil heater. The amount of fluid in the copper heating core is estimated by incrementally measuring the first, second and third thermistors after a predetermined time in the heating cycle. A revised temperature set point and revised estimated power are computed based on temperature differential of the first, second and third thermistors. The heating cycle is resumed by providing the revised estimated power to the foil heater. A dwell phase is entered when the third thermistor reaches the target temperature. Heater power is increased if the third thermistor is below the temperature set point, and decreased if the bottom thermistor is above the temperature set point.
The disclosed implementations also provide a method for battery charging with a universal power charger input. A source is connected to a universal charger input jack. A charging current pulse width modulation (PWM) is set to zero. An open circuit charging voltage (VCHG) voltage source voltage is determined and that value is stored. An interval timer counter is set and started. A previous value of VCHG voltage source voltage is stored. The VCHG voltage source voltage value is read and updated. If the voltage is not less than a shutdown limit, it is determined if the voltage is less than the previous stored voltage and, if so, the current limit setting PWM is reduced by a predetermined decrement. If the interval timer counter has not timed out storing a previous value of VCHG voltage source voltage is continued. If the interval timer has tied out, the charging current PWM set to zero. If the determination is that the voltage is not less than the previous stored voltage determine if the voltage is greater than the previous stored voltage and, if so, incrementally increase the current limit setting PWM to increase the current drawn from the source but not more than a maximum limit. If the interval timer counter has not timed out storing a previous value of VCHG voltage source voltage is resumed. If the timer has timed out charging current PWM to zero.
These and other features and advantages of the present invention will be better understood by reference to the following detailed description of exemplary embodiments when considered in connection with the accompanying drawings wherein:
[Para 14]
Implementations shown in the drawings and described herein provide a battery powered electronic stove (“E-stove”) with an integrated liquid container and heating system and a battery assembly both have a substantially cylindrical form factor allowing storage in a water bottle holder in a backpack and in a second operating mode with the battery system laterally engaged to the liquid container for increased standing stability while providing power to the heating system. The heating system and battery assembly have a rotatable connector which allows attachment in an axial mode for other storage situations like boats, cars, airplanes or at home where maintaining connection of the two units other than in the operating mode is desirable.
Referring to the drawings,
A battery assembly 40 has a second cylindrical shell 42 having a diameter substantially identical to the first cylindrical shell 14 and is axially engaged to the first cylindrical shell with a rotatable connector 38 which will be described in greater detail subsequently. The battery assembly 40 includes a battery pack 44 (shown in
In the non-operating mode, with the battery assembly 40 engaged to the liquid container and heating system 12 in axial alignment using the rotatable connector 38, the cylindrical form factor provided allows the entire E-stove 10 to be connected to maintain the elements together.
The battery assembly 40 is removable from the rotatable connector 38 for independent unit storage and for lateral engagement to the liquid container and heating system 12 to place the E-stove 10 in the operating mode as shown in
As seen in
In the exemplary embodiment, the battery cells in battery pack 44 are arranged around a pair of spacers that locate eight cells on a circular pattern with a ninth cell in the center. This produces nominal 34V output under load in a very compact, circular shape. The spacers have access holes that allow the cell tap wires to pass thru them to be attached to the Battery Protection PCB (BPPCB) 73 that is screwed into a bottom spacer. This configuration allows the battery pack and BPPCB to be fabricated and shipped as an assembly.
The LCHS 12 incorporates a copper core 80 having a solid bottom 82 to contain liquid carried in the first cylindrical shell 14 as seen in
As seen in
This configuration seals the heater compartment against water penetration which will cause the ceramic paper binder to dissolve. This is achieved by the compression gasket at the cover-shell rim and by the shrink wrap sealing the heater foil and insulation against the copper walls. A small opening 91 at the bottom of the heater compartment (seen in
As seen in
A contact switch 118 (seen in
As previously described, a universal power charger input jack 48 is provided for the battery assembly 40. The battery charger controller portion of the of the PCPCB 70 employs a boost converter 902 as shown in
Any form of DC source that can provide input voltages in the range from 9 VDC to 24 VDC may be connected to the universal power charger input jack 48, step 1001. The four primary example sources are a stiff, fixed voltage source (example: car nominal 12V power port), a current limiting DC voltage source (examples: wall plug power supply or bench power supply), a current limiting DC source (example: solar cell array), or a raw half rectified AC source (example: simple 50/60 Hz mains transformer).
The microprocessor initially reads the connector carriage sensor switch 118 to determine if the carriage is in the extended position, step 1002, and, if so, a charger 902, analog to digital converter (ADC) 906 and the microprocessor 904 circuits are turned on, step 1003. The initial charging current pulse width modulation (PWM) is set to zero, step 1004. The ADC voltage detector circuit 906 is read to determine the open circuit charging voltage (VCHG) voltage source and stores that value in a register, step 1005. The microprocessor ignores DC voltages below 9 VDC or over 24 VDC and returns to step 1001. When the microprocessor detects a voltage between 9 VDC and 24 VDC, step 1006, internal status flags are set based upon the measured value, step 1008. If the voltage is below 18.5V when first measured (at zero current load), the microprocessor assumes a current limited constant voltage source, step 1010. If the voltage is above that level, the microprocessor assumes the source is a constant current source (i.e. solar source), step 1012. These initial assumptions will be overridden if the subsequent behavior is inconsistent with the first guess.
Once the initial setup phase is completed, the microprocessor resets then starts a one minute timer counter, step 1013. A previous value of VCHG voltage source voltage is stored, step 1014, and the ADC reads and updates the VCGH voltage source voltage value, step 1015. If the voltage is less than a shutdown limit the cycle returns to step 1001. If not, a determination is made if the voltage is less than the previous stored voltage and, if so, reduces the current limit setting PWM by a predetermined decrement, step 1016. A determination is then made if the one minute timer counter has timed out and, if not, returns to step 1014. If so, the cycle returns to step 1001. If the determination that the voltage is less than the previous stored voltage is no, a determination is made if the voltage is greater than the previous stored voltage. If so, the current limit setting PWM is then incremented to increase the current drawn from the source but not more than the maximum limit that the boost converter allows, step 1017 (this is set at the factory and based upon the battery cell amp-hr rating). As the current increases, the voltage at the external power source will remain almost constant, and then begin to droop. This method provides a determination of the source type. If the source has a straightforward current overload limit, the voltage will drop abruptly. If the source has a soft (fold back) current limit, the voltage will drop more slowly. Either way, the voltage drops, and the microprocessor determines the source current limit has been exceeded. The microprocessor reduces the requested current by a few steps, and repeats observation. Once the source current limit has been reached, the microprocessor stops dithering and stays at the calculated operating point for approximately 1 minute after which it repeats the process until the battery pack 44 eventually reaches its full charge voltage of 38.6V (which is also dependent upon battery cell selected, and set at the factory). Thereafter, the battery is effectively trickle charged until the external source is removed.
A selected solar source will output a voltage near 20V and that voltage will drop as more current is demanded by the micro. However, the solar cells voltage/current behavior is different from the other sources listed in that it has a very soft characteristic, i.e., the voltage drops much more for a given increase in load. The microprocessor therefore uses a more relaxed criterion for determining when and if it needs to limit the solar source load. The operating system set point also changes with solar flux, which can change within the one-minute sampling interval. If the operating point changes significantly, the microprocessor terminates the current interval and begins a new dynamic control interval.
As seen in
The second microprocessor employs the two control buttons 33 and 35 in the indicator panel 34 that are used to set the target fluid temperature, the rate at which the heater power will be increased, and the dwell time once the target temperature has been reached before completely shutting down the heaters through the first state machine as shown in
The second microprocessor implements two processing modules in the second state machine 1112, the eco mode and the boost mode, as shown in
The boost mode simply provides power to the foil heater and measures all three thermistors 122 and the voltage of the battery pack 44. The boost mode enters a dwell phase once the bottom thermistor reaches the target temperature, step 1202. The heater is also turned off if any thermistor reaches 105C or the battery pack condition is below its shutdown limits step 1204. Assuming the battery pack is within acceptable limits, the heaters are turned back on once all thermistors readings have dropped a few degrees, step 1206.
The eco mode measures all three thermistors and the battery condition, and computes a temperature set point, step 1208. It will enter the dwell phase once the bottom thermistor reaches a target temperature, step 1210. It will increase heater power if the bottom thermistor is below the target temperature, step 1211 and decrease the heater power if the bottom thermistor is above target temperature, step 1212. The limits are chosen to optimize the thermal performance of the overall foil heater system and are based upon observed foil heater thermal performance under varying conditions, including the initial fluid starting temperature, computed estimated initial fluid volume, and the ambient temperature as shown in
The overall objective is to increase the total volume of heated fluid that can be achieved with a fresh battery as much as physically possible. Eco mode trades heating time to achieve this objective. Boost mode minimizes heating time at the expense of greater battery consumption.
Referring again to
Referring to
The disclosed implementations provide benefits including almost goof-proof connection (cannot be connected backwards), extremely good contact wiping ability, and the use of a parallel battery system/LCHS configuration which maximizes backpack storage options and stabilizes the operating stove against wind gusts (an improvement over having the heating source below the vessel which then must mount above it and use either tripod legs or the stove windshield to hold the pan). The standard arrangement puts the center of gravity much higher up than the present side mount scheme, and thus, it is less stable. The ability to merely physically separate the LCHS and battery system provides an added safety feature of instant off with disconnection of the connector. As noted, the diameter of the LCHS is adapted to fit a backpack water bottle pocket. However, both the LCHS and battery assembly may be configured with a cylindrical form factor to fit a standard vehicle cup holder. The axially connected configuration in the non-operating mode provides a method to position the battery (upside down) below the stove while securely holding both in place in a cup holder so the battery assembly can optionally be recharged by plugging its power input jack into a vehicle power port source and/or also optionally power the stove (using a small jumper cable accessory to connect the battery power output port to the stove power input port, which are both exposed when installed in a cup holder in this described manner). Once the copper heater core of the LCHS reaches temperature, the short jumper cable can be removed and the LCHS can be unscrewed from the battery assembly. The battery assembly can optionally remain held in the holder until the battery fully recharges. The LCHS can be re-stored on top of the battery assembly, or the battery assembly can be removed and the LCHS stored directly into the cup holder without any cables remaining attached where the LCHS will function in a manner similar to a thermos bottle and keep the fluid near the target temperature for several hours. This functionality enables the product to address both backpack centric and vehicle centric uses. The vehicle centric use might employ and implementation with a LCHS having approximately 5 inch height and 350 ml capacity to provide a faster and more stable configuration targeting this specific cup holder market. Such a version would have exactly the same construction except the heater power would be one half of the larger version and the copper heater core would be half as high.
Having now described various embodiments of the invention in detail as required by the patent statutes, those skilled in the art will recognize modifications and substitutions to the specific embodiments disclosed herein. Such modifications are within the scope and intent of the present invention as defined in the following claims.
Claims
1. A method for heating of a liquid container and heating system (LCHS) comprising:
- receiving an input for a desired heating mode and a temperature setting;
- providing electrical power from a battery pack that is operatively connected with a resistive heater that is in contact with a heating core;
- measuring battery pack condition before or after the step of providing;
- measuring a temperature of one or more thermal sensors connected with the heating core;
- entering a dwell phase when a measured temperature of at least one of the one or more thermal sensors reaches the temperature setting; and
- removing electrical power from the resistive heater in the dwell phase.
2. The method of claim 1, wherein the resistive heater comprises a thin-film construction.
3. The method of claim 1, wherein the resistive heater is configured to contact a lower portion of the heater core.
4. The method of claim 1, wherein the LCHS comprises two of the one or more thermal sensors that are positioned at different locations along the heating core.
5. The method of claim 1, wherein before the step of providing electrical power, operatively connecting the battery pack to the liquid container, wherein the LCHS is configured to accommodate connecting and disconnecting the battery pack from the liquid container.
6. The method of claim 5, wherein the LCHS has a compact form factor to enable the LCHS to be carried by a user for use at a remote location.
7. The method of claim 1, wherein when desired heating mode is a first heating mode, the LCHS provides full available electrical power to the resistive heater before the step of measuring battery pack condition.
8. The method of claim 7, wherein after the step of entering the dwell phase, further comprising providing electrical power to the resistive heater if after the step of entering the dwell phase the measured temperature of at least one of the one or more thermal sensors is below the temperature setting.
9. The method of claim 8, wherein before the step of providing electrical power to the resistive heater, measuring battery pack condition, and providing electrical power if the measured battery pack condition is within acceptable limits.
10. The method of claim 7, further comprising repeating the dwell phase if after the step of providing electrical power to the resistive heater the measured temperature of at least one of the one or more thermal sensors reaches the temperature setting.
11. The method of claim 1, wherein when the desired heating mode is a second heating mode, before the step of providing electrical power, the LCHS measures an initial temperature of the one or more thermal sensors and measures battery pack condition.
12. The method of claim 11, further comprising computing a target temperature and estimated electrical power to reach the target temperature based on measured battery pack condition.
13. The method of claim 12, further comprising after the step of computing, starting a heating cycle, and providing the estimated electrical power to the resistive heater.
14. The method of claim 13, wherein the one or more thermal sensors comprises two or more thermal sensors that are positioned at different locations along the heating core.
15. The method of claim 14, further comprising:
- estimating an amount of fluid in the heating core by measuring the temperatures of the two or more thermal sensors after a predetermined time in the heating cycle;
- computing a revised temperature set point and a revised estimated electrical power based on a temperature differential of the two or more thermal sensors;
- resuming the heating cycle by providing the revised estimated electrical power to the resistive heater; and
- entering a dwell phase when at least one of the two or more thermal sensors has a measured temperature that equals the revised temperature set point.
16. The method of claim 15, further comprising increasing the electrical power to the heater core when the at least one of the two or more thermal sensors has a measured temperature below the revised temperature set point.
17. A method for heating of a liquid container and heating system (LCHS) comprising the steps of:
- inputting one or both of a desired heating mode and a temperature setting;
- providing electrical power from a battery pack that is operatively connected with a resistive heater comprising a thin-film construction in contact with a heating core;
- one or both of measuring battery pack condition and measuring a temperature of thermal sensors that are positioned at different locations along the heater core before or after the step of providing;
- entering a dwell phase when a measured temperature of at least one of the thermal sensors equals the temperature setting during which time electrical power from the battery pack to the resistive heater is shut off; and
- restoring providing electrical power from the battery pack to the resistive heater when a measured temperature of at least one of the thermal sensors is below the temperature setting.
18. The method of claim 17, wherein before the step of restoring, measuring battery pack condition to determine if the battery pack condition is within acceptable limits.
19. The method of claim 17, further comprising:
- estimating an amount of fluid in the heating core by measuring a temperature of at least two of the thermal sensors after a predetermined time in a heating cycle;
- computing a temperature set point and an estimated electrical power based on a temperature differential of the measured temperatures of the at least two of the thermal sensors;
- resuming the heating cycle by providing the revised estimated electrical power to the resistive heater; and
- entering a dwell phase when at least one of the thermal sensors has a measured temperature that equals the temperature set point.
| 4095090 | June 13, 1978 | Pianezza |
| 4704954 | November 10, 1987 | Mollenhoff |
| 4801782 | January 31, 1989 | Ineson |
| 5063838 | November 12, 1991 | Matuschek |
| 5159873 | November 3, 1992 | Weeden |
| 5508494 | April 16, 1996 | Sarris et al. |
| 5680108 | October 21, 1997 | Daniell et al. |
| 7975491 | July 12, 2011 | Smisson, III |
| 20070221067 | September 27, 2007 | Scelza |
| 20110103779 | May 5, 2011 | Baston |
| 20130312617 | November 28, 2013 | Toporovsky |
| 20140165607 | June 19, 2014 | Alexander |
| 20150182059 | July 2, 2015 | Richardson |
| 20150250346 | September 10, 2015 | Baston |
| 20160345772 | December 1, 2016 | Warren et al. |
| 20170119196 | May 4, 2017 | Chen et al. |
| 20180070648 | March 15, 2018 | Monsees |
| 20180078077 | March 22, 2018 | Su |
| 20180168378 | June 21, 2018 | Alexander et al. |
| 20190090680 | March 28, 2019 | Urciuoli et al. |
| 2222260 | June 1998 | CA |
| 201429151 | March 2010 | CN |
| 106618246 | May 2017 | CN |
| 206560333 | October 2017 | CN |
| 1656866 | May 2006 | EP |
| 2289208 | November 1995 | GB |
| 2374274 | October 2002 | GB |
| 20170059100 | May 2017 | KR |
| 2007112096 | October 2007 | WO |
| 2017136311 | August 2017 | WO |
| 2018222191 | December 2019 | WO |
- Notice of Allowance dated Sep. 30, 2022 for corresponding U.S. Appl. No. 16/756,383, filed Sep. 19, 2019; total 8 pages.
- Notice of Allowability dated Oct. 18, 2022 for corresponding U.S. Appl. No. 16/756,383, filed Sep. 19, 2019; total 5 pages.
- International Search Report dated Feb. 3, 2020 for corresponding International Application No. PCT/US2019/051969 filed Sep. 19, 2019; total 4 pages.
- Written Opinion of the International Searching Authority dated Feb. 3, 2020 for corresponding International Application No. PCT/US2019/051969 filed Sep. 19, 2019; total 6 pages.
- International Preliminary Report on Patentability dated Mar. 23, 2021 for corresponding International Application No. PCT/US2019/051969 filed Sep. 19, 2019; total 7 pages.
Type: Grant
Filed: Dec 29, 2022
Date of Patent: Aug 4, 2026
Patent Publication Number: 20230175699
Inventor: Murray Ruben (Santa Barbara, CA)
Primary Examiner: Ko-Wei Lin
Application Number: 18/091,052
International Classification: F24C 7/08 (20060101); A47G 19/22 (20060101); A47G 23/04 (20060101); A47J 31/00 (20060101); F24C 7/10 (20210101); F24H 1/06 (20220101); G05B 19/02 (20060101); A47J 36/24 (20060101); H05B 1/02 (20060101);